In the public health sector, there is an increasingly clear trend toward single instrument tracking in order to be able to track the respective medical products to the field of instruments and sterile goods so as to be able to establish and track the frequency of use, the service intervals or the current storage place. For example, completeness checks of basket contents at the most different stations of an instrument circulation serve for ensuring sterile goods to be utilized completely and in the correct configuration.
Furthermore they serve for reducing the great and cost-intensive loss of instruments.
They further serve for patient safety to a particular extent. This aspect gains importance against the background that in the case of emergency operation sometimes about 100 pressing rolls and 40 pads are used apart from the other instruments. It is moreover known from hospital statistics that on average 3000 cases occur each year in which foreign matters such as cloths, swabs or the like remain in patients' bodies after surgical interventions.
Apart from traditional manual techniques such as sorting and counting in the meantime most various technologies have been employed to assist or even fully automatically run the detection of surgical instruments. These include, for instance, radio identification by means of RFID (radio frequency identification) technology, weight measurement, optical identification, barcode detection etc.
Previous solutions are frequently based on individually reading out instruments or the sterile goods, respectively, which is time-intensive. Therefore the individual manual detection of individual instruments was developed into the automated individual instrument detection. Accordingly, mainly the reduction of the processing times is in the fore so as to save time and costs. Equally high processing safety is absolutely necessary so as to facilitate automation for simultaneously saving time and costs. It is a drawback of the individual instrument detection that the reading process is very time-consuming in the case of a plurality of objects and instruments, respectively.
A further known solution therefore is to simultaneously detect a plurality of instruments to reduce the processing times in this way especially in contrast to individual readings in instrument tracking (e.g. with Data Matrix). As suggested by U.S. Pat. No. 7,118,029 B2, plural instruments marked with RFID tags (RFID instruments) lying in a basket are simultaneously detected, are compared to basket lists and possibly incorrectly sorted instruments are identified.
Since the RFID transponder at the surgical instrument cannot be configured to have any size, usually passive RFID tags which are operated by the high-frequency electromagnetic alternating field generated by the RFID reader have to be used. As the field of radiation decreases quadratically with the distance, a rather high transmission power must be applied. Especially in the medical environment this is possible to a restricted extent only so as to avoid possible interferences with other highly sensitive devices, in particular in the operating room.
In the case of this so called batch detection overlapping and covered instruments in the basket or container may entail the fact that some of the instruments to be detected are detected incorrectly or not at all by the reader used and are thus missed. Furthermore, the related poor probability of identification as well as the lower processing reliability results in the fact that the reading operation cannot be automated. As a consequence, also with this solution increased processing times and costs have to be accepted.
Since by the already known systems either high processing reliability is realized at the expense of the processing speed or a high processing speed is realized at the expense of the processing reliability and thus of automation, there is a need for action in further developing the reading systems.
Against this background, the object underlying the invention is to provide a device and a method adapted to reliably detect a plurality of different instruments simultaneously and with high identification probability.
This object is achieved by the features described herein.